Imidazole → (3-Bromo-4-methylphenoxy)(tert-butyl)dimethylsilane

Participants

Reaction Steps

3-Bromo-4-methylphenol(25.0 g, 0.134 mol) and aluminum chloride (36.11 g, 0.27 mol) were heated to 127° C. for 2 h. Ice was added, the solution extracted with ethyl acetate, dried (Na2SO4) and evaporated to dryness under reduced pressure. N,N-Dimethyl formamide (150 ml), t-butyl-dimethylchlorosilane (25.0 g, 165 mmol) and imidazole (22.6 g, 33.2 mmol) were added and the solution stirred at room temperature for 16 h. The products were partitioned between water and ethyl acetate, the organic layer separated, dried (Na2SO4) and evaporated to dryness under reduced pressure. Purification by flash chromatography using hexane as eluent gave impure 1-bromo-2-methyl-5-t-butyldimethylsilyloxybenzene (22.0 g). Carbon tetrachloride (125 ml) and N-bromosuccinimide (10.80 g, 66.6 mmol) were added and the solution heated to reflux over a 150 W light bulb for 2 h. The solution was cooled to 5° C., filtered and evaporated to dryness under reduced pressure. Purification by flash chromatography using hexane as eluent gave the title compound (12.64 g, 21%) as a white solid; δH (CDCl3) 0.21 (6H, s, Si(CH3)2), 0.97 (9H, s, t-Bu), 4.59 (2H, s, CH2Br), 6.76 (1H, dd, J 8.3 and 2.4 Hz, 4-H), 7.07 (1H, d, J 2.4 Hz, 6-H), 7.30 (1H, d, J 8.4 Hz, 3-H): m/z (E.I.) 382 (M+, 2%), 380 (M+, 4%), 378 (M+, 2%), 299 (100%): (Found: M-, 377.9647). C13H20OBr2Si requires M, 377.9650).

Provenance & Evidence